[erikbye]

https://en.wikipedia.org/wiki/Learning_curve

> The familiar expression "a steep learning curve" is intended to mean that the activity is difficult to learn, although a learning curve with a steep start actually represents rapid progress.

[austinjp]

Well, progress along the Y axis is only achieved if progress is made on the X axis too. If the curve is too steep, the user is expected to learn too much too quickly, and many will simply give up.

[derefr]

The X axis of an actual-jargon “learning curve” is effort, not time. Steeper slope means higher “learning ROI”—more learning out per unit of effort invested in.